Differences between series, parallel and tandem working modules


Hello 🙂


I hope that you are having a wonderful day! Are you ready for new portion of information? Well, whether you are ready or not I am still going to share some hydraulic knowledge 😛 This time we will talk about sectional mobile directional control valves, namely about individual sections internal connection.


When multiple 6/3 sections are sandwiched together, there are three different ways of internally connecting the individual sections: series, parallel and tandem. Below, you can find an explanation how they work 🙂 


Series circuit – The oil coming from upstream actuator flows to the downstream actuator. The sum of working pressures are limited by main relief valve setting. The return from the first valve is routed to the inlet of the second, and so on. In neutral, the oil passes through the valves in series and returns to the reservoir. When a control valve is operated, the incoming oil is diverted to the cylinder that the valve serves. Return liquid from the cylinder is directed through the return line and on to the next valve.


This system is satisfactory as long as only one valve is operating at a time. When this happens, the full output of the pump at full system pressure is available to that function. However, if more than one valve is operating, the total of the pressures required for each function cannot exceed the system’s relief setting.



Parallel circuit – all sections are powered directly from the pump, section return flow goes directly to the tank and bypass flow goes separately to tank via all downstream sections. Parallel connection does enable two or more functions to be powered simultaneously, however, the actuator requiring the lowest pressure will operate first.



Tandem circuit – only the bypass flow from upstream sections is available to power downstream sections. Regeneration and intensification between simultaneously shifted functions is not possible. And if upstream function is fully shifted, no flow is available to any downstream sections.




Can you name each section now? 😉


I hope that it was informative for you, please drop me a comment 🙂

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